Suction head for sweeping swimming pools

ABSTRACT

A suction head for use in sweeping a swimming pool bottom. A generally rectangular platform is supported for forward and backward motion perpendicular to the longitudinal axis of the platform while being maintained in spaced parallel relation above the pool bottom. Front and rear flanges along the edges of the platform, define a shallow chamber beneath it. The flanges extend downwardly into closely spaced relation from the pool bottom. A central opening in the platform is connected to a suction line. Baffles connected with the platform adjacent its outer ends extend downwardly into sliding contact with the pool bottom. The baffles prevent longitudinally inward flow of water into the chamber between the ends of the flanges and, in addition, direct water entering beneath the front flange towards the central opening. The baffles enable the length of the suction head to be increased despite the considerably reduced level of suction prevailing near the outer ends of the platform.

United States Patent [191 Levack [451 Apr. 23, 1974 SUCTION HEAD FOR SWEEPING SWIMMING POOLS [76] Inventor: Walter R. Levack, 7900 Chase Ave.,

Los Angeles, Calif. 90045 [22] Filed: Feb. 20, 1973 [21] Appl. No.: 334,160

[52] U.S. Cl. 15/].7, 15/415 [51] Int. Cl. E04h 3/20 [58] Field of Search 15/17, 415, 420

[56] References Cited UNITED STATES PATENTS 3,273,188 9/1966 Levack l5/l.7 3,509,589 5/1970 Bond l5/l.7

Primary Examiner-Edward L. Roberts Attorney, Agent, or F irm-Fulwider Patton Rieber Lee & Utecht [5 7] ABSTRACT A suction head for use in sweeping a swimming pool bottom. A generally rectangular platform is supported for forward and backward motion perpendicular to the longitudinal axis of the platform while being maintained in spaced parallel relation above the pool bottom. Front and rear flanges along the edges of the platform, define a shallow chamber beneath it. The flanges extend downwardly into closely spaced relation from the pool bottom. A central opening in the platform is connected to a suction line. Baffles con nected with the platform adjacent its outer ends extend downwardly into sliding contact with the pool bottom. The baffles prevent longitudinally inward flow of water into the chamber between the ends of the flanges and, in addition, direct water entering beneath the front flange towards the central opening. The baffies enable the length of the suction head to be increased despite the considerably reduced level of suction prevailing near the outer ends of the platform.

19 Claims, 9 Drawing Figures SUCTION HEAD FOR SWEEPING SWIMMING POOLS BACKGROUND OF THE INVENTION This invention relates to a suction head which, when it is attached to a suction line, may be used for sweeping the bottom of a swimming pool.

In sweeping the bottom of a swimming pool, it is known to utilize suction cleaning systems comprising a flexible suction line, which communicates with a suction source such as the pool circulation pump, connected to a suction head which distributes the suction over the pool bottom beneath the suction headfUndesirable matter on the bottom of the pool, such as accumulations of dirt, particulate material, leaves and the like, which will be collectively referred to hereinafter as silt, are drawn up the suction line out of the pool for removal. The suction head is moved manually across the pool bottom by a handle attached to the suction head to leave a swept area behind the suction head in which the silt has been removed. A prior device of this type is disclosed, for example, in applicants prior US. Pat. No. 3,273,188.

Although generally satisfactory, such prior devices have been limited in the effective width of the path that can be cleared in a single pass of the suction head. Because the suction applied at the center of the suction head decreases rapidly as the distance from the center increases, the relatively limited suction available at residential pools has, as a practical matter, generally limited effective width of the suction head to not more than approximately 1 l and 1% inches. Because it would be desirable to sweep a wider path on a single pass in order to reduce the total number of passes necessary to clean a pool, efforts have been made to develop a suction head of greater width using the same available suction pressure.

One favored approach has been to provide open outer ends on the suction head on the theory that an additional lateral flow of water directly through the head to the suction opening will be created which will remove additional silt lying just outside the ends of the suction head, thereby providing a widened cleaning path. This approach has not met with much success because the low residual suction pressure available at the ends of the suction head attracts the silt laden water in at only a relatively low velocity which may be less than that at which the suction head is being moved through the water. The resultant velocity may be such that the water never reaches the suction outlet but instead travels into the swept region behind the platform and deposits the silt there. As a result, the net swept width is not effectively increased, and may even be reduced.

Another problem sometimes associated with prior devices is the tendency for some leaves to pass over rather than under the suction head. For example, if the leading edge of the suction head extends straight down, a leaf may become trapped against it and eventually the forward movement of the head will free the leaf so that it passes over rather than under the suction head. The problem is particularly acute near the ends of the suction head where the residual suction available to draw the leaf under the suction head is relatively low compared with the water forces acting on the leaf, due to the motion through the water, which tend to carry the leaf over the upper side of the platform.

Another concern which is of particular interest to commercial pool cleaning operators arises from the fact that most residential pools have available a lower suction line pressure than is available from many commercially or institutionally operated pools. When cleaning a pool of the latter type, the operator would like to be able to take advantage of the higher suction line pressure available to utilize a wider suction head than that used for cleaning a residential pool. It would therefore be desirable to provide a suction head for use in cleaning residential pools which could be readily combined with additional assemblies to provide a suction head of greater length suitable for pools where a greater suction line pressure is available.

SUMMARY OF THE INVENTION A suction head for a swimming pool cleaner, constructed in accordance with the invention, is intended to provide a swept region behind the suction head which is of greater width than heretofore possible, uti lizing the same suction line pressure. In addition, the suction head is designed to perform with an improved leaf removal capability, by the provision of structure which facilitates the passage of leaves through the underside of the device.

More particularly, a suction head, constructed in accordance with the present invention, includes a generally planar platform extending in longitudinal and transverse directions. Wheels support the platform for forward and backward motion perpendicular to its longitudinal axis while maintaining the platform spaced above the pool bottom in adjacent, generally parallel relation thereto. Front and rear flanges along the front and rear longitudinal edges of the platform, extend downwardly intoclosely spaced relation from the pool bottom. The flanges define a shallow chamber beneath the platform. An opening extending generally centrally through the platform is adapted for connection to a suction line. Two baffles are secured to the underside of the platform adjacent its opposite ends and extend into contact with the pool bottom. The baffles substantially prevent passage of water in a longitudinally inward direction between the flanges into the chamber at its ends.

By preventing longitudinally inward flow of water at the ends of the chamber, thereby adopting an approach which is opposite to that widely thought necessary in the prior art to extend the swept width, the problems of drawing in and depositing silt within the swept region downstream of the platform are avoided. In addition, the residual suction available at the ends of the platform is conserved by the closed longitudinal ends, enabling the longitudinal edges of the suction head to be increased in length to take advantage of the suction available. As a result, a suction head of greater length can be constructed which provides a swept region of greater width without the problem of deposition of silt within the swept region.

Each baffle unit is of generally triangular configuration having concavely curved vertical walls extending longitudinally and transversely inwardly towards the suction inlet opening and meeting at an apex spaced from the opening. The upstream wall of the baffle unit directs flow entering beneath the upstream longitudinal flange, in an inclined direction towards the suction inlet. In so doing the baffle also prevents direct transverse flows through the chamber in the regions of weakest suction pressure, which might otherwise bypass the suction inlet and deposit silt in the swept region. The baffle unit is symmetrically configured so that on the return stroke, when the suction head is brought back in the opposite direction, the reverse side of the baffle unit functions as the upstream wall.

To facilitate the passage of leaves under the suction head, so that they do not tend to skip over the suction head and remain in the pool, the flanges along the front and rear edges of the platform are rounded and curved downwardly and inwardly below the platform. Leaves attracted by the suction applied along the lower edge of the flange, impinge upon it and are guided downwardly by the curved surface beneath the flange into the chamber during the continued motion of the suction head.

A suction head according to the present invention is so constructed that the length of the suction head may readily be increased to provide a larger unit for use in cleaning pools where a larger source of suction line pressure is available. Thus an additional sub-assembly containing further extended portions of the baffle unit may be attached to the outer longitudinal ends of the unit and fixedly secured thereto, to provide a larger suction'head using readily assembled structural parts.

BRIEF DESCRIPTION OF THE DRAWINGS A suction head for sweeping a swimming pool bottom, constructed in accordance with a preferred embodiment of the invention, is illustrated in the accompanying drawings in which:

FIG. 1 depicts in a simplified manner a prior art suction head, illustrating the problem of silt deposition within the swept region extending downstream of the suction head, arising from flow through open end extremities of the suction head;

FIG. 2 is a perspective view of a suction head constructed in accordance with the preferred embodiment of the invention, attached to an external suction line;

FIG. 3 is a view of a portion of the underside of the suction head shown in FIG. 2 looking in the direction indicated by the arrow 3 therein;

FIG. 4 is a cross-sectional view of the suction head shown in FIG. 3 taken on the lines 44 therein;

FIG. 5 is a crosssectional end view of the suction head shown in FIG. 3 taken along the lines 55 therein;

FIGS. 6 and 7 are cross-sectional end views of two portions of the suction head shown in FIG. 3, taken along the lines 6-6 and 77 therein, respectively, illustrating the curved flange forming a part of the suction head;

FIG. 8 is an exploded. perspective view of separable center and outer sub-assemblies forming the suction head shown in FIG. 3, prior to their connection together; and

FIG. 9 is a bottom view of an end portion of the center sub-assembly shown in FIG. 8 prior to removal of certain end wall portions of the center sub-assembly.

DETAILED DESCRIPTION A suction head, according to the present invention is intended to enable sweeping a wider path of the pool surface in a single pass of the suction head than heretofore possible, utilizing the same available suction pressure. Certain prior art devices, illustratively shown in FIG. I, attempted to achieve this result by opening the ends of the suction head for longitudinally inward flows of water. With such a prior arrangement, because the suction pressure at the ends is at a low level, the longitudinally inward velocity imparted to the incoming water at the ends of the suction head was comparable to, or less than, the velocity of motion of the device through the water. As a result, silt-laden incoming water could pass out of the suction head into the swept region to deposit the silt there, without ever reaching the suction inlet. The suction head of the present invention provides enlarged length without the disadvantages of the prior art just described.

A suction head (FIG. 2), constructed in accordance with the preferred embodiment of the invention, includes a platform 2 of generally rectangular configuration provided on its upper surface with a plurality of longitudinally spaced, transverse stiffening ribs 4. Additional wheel mounting ribs 6, which extend beyond the edges of the platform, are provided with vertically adjustable mountings 8 for wheels 10. The wheels 10 support the platform 2 in spaced parallel relation above the bottom of the pool for forward and backward motion in opposite transverse directions perpendicular to the longitudinal axis of the platform. At approximately the center of the platform there is mounted a suction inlet pipe 12 communicating with the underside of the platform 2. The suction inlet pipe is connected via a flexible conduit 14 to a suitable suction source, such as the pump in the circulatory system of the swimming pool, to draw water from the underside of the platform upwardly through the flexible conduit 14 and out of the pool. A fitting 16 secured to the upperside of the platform adjacent the suction inlet pipe 12 is hingedly connected to the lower end of a handle 18 which may be manipulated by a workman standing at the edge of the pool to move the suction head to and fro. The platform 2 may be made out of material possessing sufficient flexibility to permit the entire suction head to flex in a longitudinal direction to conform to the underlying pool surfaces on which it rests. Inasmuch as the foregoing structure corresponds generally to the structure described in applicants prior U. S. Pat. No. 3,273,188, the description of that patent is incorporated herein by reference.

The platform 2 is provided along its front and rear longitudinal edges with front and rear flanges 22 and 24. When the platform is pushed in a forward direction, indicated by the arrow in FIG. 3, the front flange 22 is the upstream flange and the rear flange 24 is the downstream flange. On the pull stroke, moving the platform in a backward direction, the relative upstream and downstream positions are reversed. Each of the flanges 22 and 24 extends downwardly from the platform into closely spaced relation from the bottom of the pool leaving a narrow gap 26 (FIG. 4) sufficient for passage of silt and leaves into a shallow chamber 25 under the platform defined by the flanges. As the platform is moved across the pool bottom, there is a flow of water into the chamber 25 through the gap 26 beneath the upstream flange 22 due to the motion of the device through the water and to the suction applied. The incoming water traverses the chamber 25 toward the suction pipe 12 from which is removed through the conduit l4.

Because the influence of the applied suction decreases progressively with longitudinal distance away from the suction inlet 12, the available suction in the outer longitudinal regions of the chamber is relatively weak. In these outer regions there might exist a possibility that silt-laden water entering under the upstream flange 22 could pass through the chamber, bypassing .the inlet, into the downstream swept region behind the suction head and deposit the silt there.

To prevent this possibility, the suction head is provided with two, generally triangular, baffles 30 at each longitudinal end of the platform. Each baffle unit 30 extends vertically between the underside of the platform 2 into substantially flush contact with the pool bottom and completely prevents longitudinal inward passage of water beneath the platform between the upstream and downstream flanges at its longitudinal ends. The upstream side of each baffle 30 directs the incoming flow of water in the regions of weakest suction pressure at the ends of the chamber 25, towards the suction inlet pipe 12. Each baffle 30 extends inwardly for sufficient longitudinal distance to insure that the incoming water is carried into a region where the suction pressure is sufficiently high to complete the movement of the water to the suction inlet 12. Thus, the baffles 30 enable the length of the suction head to be increased while preventing silt-laden water from bypassing the suction inlet. In addition, because there is no loss of pressure due to flow of fluid through the longitudinal ends of the suction head, the suction pressure is somewhat conserved adjacent the ends of the platform 2 further assisting in enabling the length of the suction head to be extended. Because of the increased length of the suction head, it sweeps a path which is wider than could heretofore be obtained with the suction pressures commonly available.

Each baffle unit 30 (FIG. 3) includes vertically extending, oppositely facing, front and rear walls 34 and 36 extending vertically down from the platform into sliding contact with the pool surface. When moving forward, the front wall 34 is the upstream wall and the rear wall 36 is the downstream wall. The walls 34 and 36, which are concavely curved, have a mirror-image relation on opposite sides of the longitudinal center axis of the platform 2 and join at a rounded apex 38. The position of the apex 38 of each baffle in relation to the suction inlet 12 is such that water directed along the walls 34 and 36 enters a region in which the suction pressure is at a sufficiently high level to insure that the water completes its journey to the suction inlet. Suitable cross-bracing is provided between the walls 34 and 36 to maintain their rigidity and position. An end wall 40, vertically coextensive with the walls 34 and 36, extends between the upstream and downstream flanges 24 and 22 and is continuous with the outermost wheel mounting rib 6. It will be understood that when the suction head is moved in the reverse direction, the downstream vertical wall 36 functions as the upstream wall in directing the incoming flow of liquid toward the suction inlet.

To insure the optimum utilization of the progressively reducing suction available in the region adjacent the longitudinal ends of the chamber 25, the front and rear flanges 22 and 24, in their regions generally aligned with the adjacent baffles 30, are vertically tapered in a longitudinally outward direction (FIGS. 4, 6 and 7). The taper progressively increases the size of the gap 26 between the flange and the pool bottom. As the gap 26 is progressively increased, the resistance to flow through the gap is progressively reduced thereby helping to compensate for the progressively reducing suction pressure available in the end region of the chamber.

Assistance in guiding the flow of water within the chamber 25 towards the suction inlet 12, is provided by two longitudinally extending ribs 42 positioned in closely spaced parallel relation to the flanges 22 and 24. The longitudinal extremities of the ribs 42 are spaced longitudinally inwardly from the apexes 38 of the baffle units.

The opportunity for leaves to skip over the suction head as it is moved through the pool is minimized by rounding the outer surface of the upstream and downstream flanges 22 and 24 so that it curves downwardly and transversely inwardly to guide leaves underneath the platform. In addition, to prevent leaves becoming jammed between each flange and its adjacent one of the ribs 42, the latter are also curved downwardly and transversely inwardly so that leaves slide easily over them also.

To facilitate the construction of a suction head which may be assembled in two different length dimensions, dependent whether the suction line pressure available is the normal residential pressure or the higher pressure available in commercial installations, the platform 2 is constructed in the form of a center sub-assembly 44 and two outer subassemblies 46 (FIG. 8). The center sub-assembly 44 includes the previously mentioned suction tube inlet 12 and extends longitudinally in opposite directions therefrom to a total length appropriate for the suction line pressure available from the usual residential pool circulation pump. To each end of the center sub-assembly there can be connected one of the previously mentioned outer sub-assemblies 46. For this purpose, upwardly extending abutting flanges 48 and 49 are provided on the center and outer subassemblies through which suitable threaded connectors 52 may be passed. When the inner and outer subassemblies are bolted together, their line of separation 53 extends transversely across the entire suction head intersecting the baffle unit 30 (FIG. 3) to divide it into a truncated inner baffle portion 54 (FIG. 8) and an outer baffle portion 56 which together form the baffle 30 previously described.

The center sub-assembly 44 may be used alone as a suction head to clean a residential pool. To close the longitudinal ends of the inner assembly to prevent longitudinally inward flow for the reasons previously described, an end wall 58 (FIG. 9) extends between the flanges 22 and 24 and the inner baffle portion 54 with which it is vertically coextensive. When the outer subassembly 46 is to be. connected to the center subassembly 44, the portions of the end wall 58 between the inner baffle unit 54 and the adjacent upstream and downstream flanges are trimmed away with a knife or similar device (FIG. 8) prior to connecting the subassemblies. Thus, an operator who possesses the inner assembly, suitable by itself for use in cleaning a residential size pool, needs only to buy the additional outer sub-assemblies and connect them to his existing unit to have an enlarged length suction head suitable for taking advantage of the higher suction pressure available at a commercial pool.

An additional feature of the invention resides in the provision of structure causing an upwardly bowed transverse curvature to the platform 2. Between each adjacent pair of the wheel mounting ribs 6, a generally rectangular, heavy metallic weight 60 (FIG. 2) is positioned. The weights 60 aid in holding the suction head firmly against the bottom of the pool. Each of the weights 60 (FIG. 5) has a flat horizontal lower surface 62 and a central vertical opening through which passes a molded vertical stub 64 on the upper surface of the platform 2. A threaded connector bearing against the upper surface of the weight 60 engages the stub 64 and may be tightened to draw the platform upwardly relative to the weight. Spacers 66 are positioned between the under surface 62 of the weight and the edges of the platform so that, as the connector is tightened, the platform assumes a transversally bowed configuration. This bowed configuration assists in guiding the water to the suction inlet 12.

To further assist the distribution of the suction pressure towards the longitudinal ends of the chamber, the opening to the suction inlet tube 12 is surrounded by a generally oval-shaped, upwardly extending, shallow depression formed in the underside of the platform 2. The apexes of the oval-shaped depression 70 extend toward, and are spaced from the apexes of the baffle units 30.

Although the suction head has been described with reference to one preferred embodiment, it will be understood by one skilled in the art that modifications may be made which will still embody the spirit of the invention herein described.

I claim:

1. A suction head for sweeping a swimming pool bottom'utilizing a suction line connected to a source of suction, the suction head comprising;

a platform extending in longitudinal and transverse directions, said platform having spaced longitudinal edges,

means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto,

upstream and downstream flanges extending along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom,

an opening extending vertically through said platform generally centrally thereof, said opening on its upper side adapted for connection to the suction line; and

flow directing means connected with said platform adjacent the longitudinal ends thereof for substantially preventing passage of water in a longitudinally inward direction into said chamber between the ends of said flanges and for directing water which enters said chamber in a transversely inward direction beneath said upstream flange towards said opening.

2. A suction head as defined in claim 1 wherein said flow directing means includes,

two baffles secured to said platform, said baffles positioned adjacent the opposite longitudinal ends of said platform extending downwardly into sliding contact with the pool bottom, each said baffle on the upstream side thereof having,

an upstream flow directing surface positioned to direct water entering said chamber beneath said upstream flange adjacent the ends thereof towards said opening.

3. A suction head as defined in claim 2 wherein each said baffle extends transversely substantially the complete distance between the adjacent said upstream and downstream flanges to prevent water entering longitudinally between said flanges.

4. A suction head as defined in claim 3 wherein each said baffle on the downstream side thereof further includes,

downstream flow directing surfaces of substantially mirror-image configuration to said upstream flow directing surfaces, whereby said downstream flow directing surfaces function in the same manner as said upstream flow directing surfaces when said platform is moved in a reverse direction to said one direction. i

5. A suctionhead as defined in claim 2 wherein said platform is generally rectangular and each said upstream flow directing surface includes,

a vertically extending upstream wall facing in an upstream direction, said wall extending in a transversely and longitudinally inward direction from a location adjacent said upstream flange toward said opening, said wall directing flow of water entering beneath said upstream flange in a direction toward said opening.

6. A suction head for sweeping a swimming pool bottom utilizing a suction line connected to a source of suction, the suction head comprising;

a platform extending in longitudinal and transverse directions, said platform having spaced longitudinal edges,

means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto,

upstream and downstream flanges along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom,

an opening extending through said platform generally centrally thereof, said opening on its upperside adapted for connection to the suction line,

two baffles secured to said platform, said baffles positioned adjacent the opposite longitudinal ends of said platform, each said baffle including, upstream and downstream walls extending vertically from said platform into sliding contact with the pool bottom, said upstream and downstream walls connected with the adjacent longitudinal extremities of said upstream and downstream flanges, respectively; at least a portion of said upstream wall being inclined in a downstream and longitudinally inward direction, at least a portion of said downstream wall being inclined in an upstream and longitudinally inward direction; and

an apex connecting said inclined portions of said walls.

7. A suction head as defined in claim 6 wherein each said flange adjacent each of its longitudinal extremities is provided with a tapered portion, said tapered portion being of progressively reducing vertical extent in a longitudinally outward direction to thereby progressively increase the gap between said flange and the pool bottom in a longitudinally outward direction in the region aligned with the adjacent said baffle, whereby the resistance to inflow of water is progressively reduced to compensate for the progressively reducing suction pressure prevailing adjacent the outer longitudinal ends of said chamber.

8. A suction head as defined in claim 6 wherein said upstream and downstream walls include transverse portions extending in a transverse direction from said inclined portions of said walls into contact with said upstream and downstream flanges, respectively.

9. A suction head as defined in claim 6 wherein each said baffle further includes,

a transverse end wall connecting the ends of said inclined portions of said upstream and downstream walls remote from said apex.

, 10. A suction head as defined in claim 6 wherein said platform adjacent at least one longitudinal end thereof, further includes,

separable center and outer sub-assemblies releasably connected together along a transversely extending separation line which intersects said baffle interme diate the apex thereof and the outer ends of said inclined portions of said walls; and

cut-away wall portions on said center subassembly extending adjacent said line of separation between said upstream and downstream walls and said upstream and downstream flanges respectively in a transverse direction, said cut-away wall portions preventing flow of water in a longitudinally inward direction between said flanges and the adjacent said walls, thereby enabling said center assembly to be used independently prior to connection thereto of said outer sub-assembly.

II. A suction head as defined in claim 6 wherein said inclined portions of said upstream and downstream walls are concavely curved.

12. A suction head as defined in claim 6 wherein said opening is oval shaped and extends with its greater dimension facing towards said apexes of said baffles.

13. A suction head as defined in claim 6 further including,

upstream and downstream ribs spaced closely adjacent and parallel to said upstream and downstream flanges, said flanges and said ribs being curved in a downward and transversely inward direction on the outward facing surfaces thereof to facilitate the passage of leaves over said surfaces enroute to said opening.

14. A suction head as defined in claim 6 further including,

means for applying an upwardly bowed, transverse curvature to the underside of said platform.

15. A suction head as defined in claim 14 wherein said means for applying curvature includes,

at least one weighted member resting on the upper surface of said platform, said weighted member having a generally horizontal lower surface,

spacing members interposed between said lower surface of said weighted member and the upper surface of said platform adjacent said upstream and downstream longitudinal edges thereof; and connector means extending between said weighted member and said platform adjacent the center thereof for drawing said platform towards said weighted member to thereby cause an upwardly bowed curvature of said platform.

16. A suction head as defined in claim 5 wherein said upstream wall is configured as a smooth, concave, curve.

17. A suction head as defined in claim 1 further including,

means for applying an upwardly bowed, transverse curvature to the underside of said platform.

18. A suction head as defined in claim 2 further including,

upstream and downstream ribs spaced closely adjacent and parallel to said upstream and downstream flanges, said flanges and said ribs being curved in a downward and transversely inward direction on the outward facing surfaces thereof to facilitate the passage of leaves over said surfaces enroute to said opening. 19. A suction head for sweeping a swimming pool bottom utilizing a suction line connected to a source of suction, the suction head comprising,

a platform extending in longitudinal and transverse directions, said platform having spacedlongitudinal edges, means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto, upstream and downstream flanges along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom, each said flange adjacent each of its longitudinal extremities being provided with a tapered portionof progressively reducing vertical extent in a longitudinally upward direction to thereby progressively increase the gap between said flange and the pool bottom, an opening extending through said platform generally centrally thereof, said opening on its upper side adapted for connection to the suction line, two baffles secured to said platform, said baffles positioned adjacent opposite longitudinal ends of said platform, each said baffle including, upstream and downstream walls extending vertically from said platform into sliding contact with the pool bottom, said upstream and downstream walls connected with the adjacent longitudinal extremities of said upstream and downstream flanges, respectively; at least a portion of said upstream wall being inclined in a downstream and longitudinally inward direction, at least a portion of said downstream wall being inclined in an up stream and longitudinally inward direction;

an apex connecting said inclined portion of said wall; and

means for applying an upwardly bowed, transverse curvature to the underside of said platform. 

1. A suction head for sweeping a swimming pool bottom utilizing a suction line connected to a source of suction, the suction head comprising; a platform extending in longitudinal and transverse directions, said platform having spaced longitudinal edges, means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto, upstream and downstream flanges extending along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom, an opening extending vertically through said platform generally centrally thereof, said opening on its upper side adapted for connection to the suction line; and flow directing means connected with said platform adjacent the longitudinal ends thereof for substantially preventing passage of water in a longitudinally inward direction into said chamber between the ends of said flanges and for directing water which enters said chamber in a transversely inward direction beneath said upstream flange towards said opening.
 2. A suction head as defined in claim 1 wherein said flow directing means includes, two baffles secured to said platform, said baffles positioned adjacent the opposite longitudinal ends of said platform extending downwardly into sliding contact with the pool bottom, each said baffle on the upstream side thereof having, an upstream flow directing surface positioned to direct water entering said chamber beneath said upstream flange adjacent the ends thereof towards said opening.
 3. A suction head as defined in claim 2 wherein each said baffle extends transversely substantially the complete distance between the adjacent said upstream and downstream flanges to prevent water entering longitudinally between said flanges.
 4. A suction head as defined in claim 3 wherein each said baffle on the downstream side thereof further includes, downstream flow directing surfaces of substantially mirror-image configuration to said upstream flow directing surfaces, whereby said downstream flow directing surfaces function in the same manner as said upstream flow directing surfaces when said platform is moved in a reverse direction to said one direction.
 5. A suctionhead as defined in claim 2 wherein said platform is generally rectangular and each said upstream flow directing surface includes, a vertically extending upstream wall facing in an upstream direction, said wall extending in a transversely and longitudinally inward direction from a location adjacent said upstream flange toward said opening, said wall directing flow of water entering beneath said upstream flange in a direction toward said opening.
 6. A suction head for sweeping a swimming pool bottom utilizing a suction line connected to a source of suction, the suction head comprising; a platform extending in longitudinal and transverse directions, said platform having spaced longitudinal edges, means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto, upstream and downstream flanges along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom, an opening extending through said platform generally centrally thereof, said opening on its upperside adapted for connection to the suction line, two baffles secured to said platform, said baffles positioned adjacent the opposite longitudinal ends of said platform, each said baffle including, upstream and downstream walls extending vertically from said platform into sliding contact with the pool bottom, said upstream and downstream walls connected with the adjacent longitudinal extremities of said upstream and downstream flanges, respectively; at least a portion of said upstream wall being inclined in a downstream and longitudinally inward direction, at least a portion of said downstream wall being inclined in an upstream and longitudinally inward direction; and an apex connecting said inclined portions of said walls.
 7. A suction head as defined in claim 6 wherein each said flange adjacent eAch of its longitudinal extremities is provided with a tapered portion, said tapered portion being of progressively reducing vertical extent in a longitudinally outward direction to thereby progressively increase the gap between said flange and the pool bottom in a longitudinally outward direction in the region aligned with the adjacent said baffle, whereby the resistance to inflow of water is progressively reduced to compensate for the progressively reducing suction pressure prevailing adjacent the outer longitudinal ends of said chamber.
 8. A suction head as defined in claim 6 wherein said upstream and downstream walls include transverse portions extending in a transverse direction from said inclined portions of said walls into contact with said upstream and downstream flanges, respectively.
 9. A suction head as defined in claim 6 wherein each said baffle further includes, a transverse end wall connecting the ends of said inclined portions of said upstream and downstream walls remote from said apex.
 10. A suction head as defined in claim 6 wherein said platform adjacent at least one longitudinal end thereof, further includes, separable center and outer sub-assemblies releasably connected together along a transversely extending separation line which intersects said baffle intermediate the apex thereof and the outer ends of said inclined portions of said walls; and cut-away wall portions on said center subassembly extending adjacent said line of separation between said upstream and downstream walls and said upstream and downstream flanges respectively in a transverse direction, said cut-away wall portions preventing flow of water in a longitudinally inward direction between said flanges and the adjacent said walls, thereby enabling said center assembly to be used independently prior to connection thereto of said outer sub-assembly.
 11. A suction head as defined in claim 6 wherein said inclined portions of said upstream and downstream walls are concavely curved.
 12. A suction head as defined in claim 6 wherein said opening is oval shaped and extends with its greater dimension facing towards said apexes of said baffles.
 13. A suction head as defined in claim 6 further including, upstream and downstream ribs spaced closely adjacent and parallel to said upstream and downstream flanges, said flanges and said ribs being curved in a downward and transversely inward direction on the outward facing surfaces thereof to facilitate the passage of leaves over said surfaces enroute to said opening.
 14. A suction head as defined in claim 6 further including, means for applying an upwardly bowed, transverse curvature to the underside of said platform.
 15. A suction head as defined in claim 14 wherein said means for applying curvature includes, at least one weighted member resting on the upper surface of said platform, said weighted member having a generally horizontal lower surface, spacing members interposed between said lower surface of said weighted member and the upper surface of said platform adjacent said upstream and downstream longitudinal edges thereof; and connector means extending between said weighted member and said platform adjacent the center thereof for drawing said platform towards said weighted member to thereby cause an upwardly bowed curvature of said platform.
 16. A suction head as defined in claim 5 wherein said upstream wall is configured as a smooth, concave, curve.
 17. A suction head as defined in claim 1 further including, means for applying an upwardly bowed, transverse curvature to the underside of said platform.
 18. A suction head as defined in claim 2 further including, upstream and downstream ribs spaced closely adjacent and parallel to said upstream and downstream flanges, said flanges and said ribs being curved in a downward and transversely inward direction on the outward facing surfaces thereof to facilitate the passage of leaves over said surfaces enroute to said opeNing.
 19. A suction head for sweeping a swimming pool bottom utilizing a suction line connected to a source of suction, the suction head comprising, a platform extending in longitudinal and transverse directions, said platform having spaced longitudinal edges, means supporting said platform for motion in at least one transverse direction perpendicular to the longitudinal axis of said platform while maintaining said platform spaced above the pool bottom in generally parallel relation thereto, upstream and downstream flanges along said longitudinal edges of said platform on the upstream and downstream sides thereof, said flanges defining a shallow chamber beneath said platform, said flanges extending downwardly into closely spaced relation from the pool bottom, each said flange adjacent each of its longitudinal extremities being provided with a tapered portion of progressively reducing vertical extent in a longitudinally upward direction to thereby progressively increase the gap between said flange and the pool bottom, an opening extending through said platform generally centrally thereof, said opening on its upper side adapted for connection to the suction line, two baffles secured to said platform, said baffles positioned adjacent opposite longitudinal ends of said platform, each said baffle including, upstream and downstream walls extending vertically from said platform into sliding contact with the pool bottom, said upstream and downstream walls connected with the adjacent longitudinal extremities of said upstream and downstream flanges, respectively; at least a portion of said upstream wall being inclined in a downstream and longitudinally inward direction, at least a portion of said downstream wall being inclined in an upstream and longitudinally inward direction; an apex connecting said inclined portion of said wall; and means for applying an upwardly bowed, transverse curvature to the underside of said platform. 